This invention relates generally to the field of leveling recreational vehicles (RV's) such as camp trailers, motor homes, etc. Specifically, it involves the field of fluid actuated leveling devices that act upon the wheels of an RV to achieve a desired, usually level configuration. The invention is designed to improve and simplify the leveling procedure for RV's.
Existing systems for leveling RV's usually require that the wheels be raised or lowered to a set, level position. These methods include parking the wheels on top of wood blocks, rocks, sticks, mechanical ramps, pneumatic ramps, and plastic and rubber blocks. The wheel(s) often need to be in an exact position. This may be on top of the item or at the right position on a ramp or in a hole for a proper configuration. This aspect of specifically configuring an RV to a usually level orientation distinguishes the field of the present invention from fields such as those involving emergency applications and those presenting devices designed for maintenance or repair and other such precisely defined actions. In the emergency device field, products are designed to be used infrequently and for a focused event (i.e., to change a tire). They do not need to withstand the elements or be as durable as designs for the present field. Further, the tire cannot be used for support or it could not be removed. In the maintenance or repair field, a precise and often repetitive event is achieved under fairly controlled circumstances. Further, the person accomplishing the event is usually well trained for the specific task. Unlike each of these, devices in the field of the present invention must be designed quite differently to adapt to persons with widely varying skills and capabilities and to achieve their purposes under not only varying circumstances but also under instances where the limits of the device may not be fully appreciated. Inventions in this field need to be designed to be used by one person who may also drive the vehicle.
In use, RV's usually need to be close to level for normal living conditions. For sleeping, it can be important not to have your feet higher than your head. Cooking can be a problem if the cooking oil or liquid goes to one side of the pan. In addition, some RV refrigerators may not work if not fairly level.
Leveling with wood blocks, rocks, sticks, ramps, plastic blocks and rubber blocks, often require the wheels to be going up an incline and then to be stopped in an exact position. These leveling devices are all susceptible to moving when the wheel starts up on them. If the blocks, or other device moves, this can mean starting the leveling procedure all over again. Similarly, if the vehicle wheels go too far, it may be necessary to start the leveling procedure over again.
Leveling with wood blocks usually requires having a number of blocks for different amounts of adjustment as may be needed to level the vehicle at different campsites. Blocks can be difficult to park on especially if the vehicle is tandem wheeled. Often people carry short blocks for easier storage as well a large variety of sizes and thicknesses for different requirements. The short blocks have a tendency to slip or fall when moving vehicle tires upon them. Not having the right quantity of blocks under the wheels to make it level when the vehicle is parked on the blocks is quite common--and frustrating. Wood blocks break, get cut up for firewood or used for other purposes at home and must be replaced. When using wood blocks, the vehicle is normally going up an incline and then must be stopped while the wheels are on top of the blocks. This is easier said than done, because once on top of the blocks, the vehicle tires roll easily, making it difficult to stop before rolling off the short blocks.
Leveling with sticks and rocks is very difficult, because normally the correct size stick or rock cannot be found. It is even more difficult to get the vehicle tires on the rocks or sticks, since they are more apt to move or fall. It is almost guaranteed that it will take several tries and still not be level . . . frustrating to say the least.
Leveling with plastic blocks can also require having a number of blocks. The user may have to move off of the blocks and reset their height to be level. The blocks may also move when trying to park on them. For leveling, the vehicle may be going up an incline and have to be stopped right on top. As mentioned earlier, this is easier said than done.
Leveling with a tapered ramp can require that the vehicle be moved up an incline and then stopped at the exactly correct position. Usually, the vehicle must not be allowed to move from this position if it is to be kept level. This procedure is difficult to do. The ramp may want to tip or move when the wheel starts up the incline. If the vehicle is a trailer, it can be even more difficult to keep in position and block. If the vehicle goes too far and goes over the end of the ramp it could cause damage to the vehicle by tipping the front of the ramp up and catching the bottom of the vehicle and the wheel at the same time. As in many of the existing systems, this is fairly typical--seemingly simple systems actually are difficult to implement and can also have extremely undesirable failure modes. Many do not have good failsafe designs.
Leveling a recreational vehicle through a pneumatic ramp has been known. In U.S. Pat. No. 3,990,681, this is disclosed through the presentation of a device which is essentially an inflatable ramp. The device is inflated and then driven up on. It may then be lowered to achieve the configuration desired. As with any ramp-based system, this device requires skill and coordination to achieve proper positioning. Further, the top of the ramp is disclosed to be fairly rigid. As mentioned earlier, the rigid ramp-based design actually increases the challenge of proper positioning. As disclosed, the ramp is to be inflated before using. The disclosure suggests that this be accomplished at a service station and that the ramp should be hauled inflated. Obviously this is bulky and takes up enormous space. If the inflatable ramp were designed for a tandem wheel vehicle, it would have to be approximately 8 ft or longer when stored. In addition, if too much air is let out of the ramp, the vehicle would need to be moved off the ramp; the ramp would need to be reinflated likely offsite, and the vehicle would then be re-driven back up the ramp, hoping to let the correct amount of air out this time. Such inconveniences are undesirable. As to storage, even when all the air is out of the ramp, there still appears to be a long hard-surface item to handle and store.
Thus, existing systems for leveling a RV are not adequate in several regards. Blocks and the like are not capable of the type of infinite adjustment a pneumatic or hydraulic system can achieve. Ramps require going up an incline or stopping on an incline. This must be avoided if the system is to be easily implemented. For the same reason even the existing pneumatic ramp-based systems are inadequate as stopping at a fairly exact position is too challenging. Further, systems should not be moving or flexing when trying to park the vehicle. The appropriate system should not only be cost-effective, it should not require considerable effort, and should not need two people to efficiently implement. It should not be a source of frustration on one's vacation.
The present invention overcomes all of these limitations. It does not move when driven on, and only requires the vehicle tire to approximately be positioned. Like parking on a piece of carpet, it is easy to use. If the vehicle wheels go too far, all that is required, is to move the vehicle wheel back by backing up into the right position. It is not necessary to start the complete procedure all over, as with blocks or ramps (pneumatic or not). You do not have to haul additional elements that may or may not be needed.
The invention will not be used for fire wood and will not break after a few uses. It will not soak up water and then crack and split. It will not sink in mud, and can easily be washed off or cleaned. The invention is a one piece assembly and is infinitely adjustable for leveling any RV design.
By presenting a system which can be achieved through both apparatus and methods, the invention goes beyond the teachings of those who have sought to achieve simple leveling of an RV. This may be surprising, however, it should be understood that although there was a long felt need to have a simple and inexpensive separate system to level an RV, this need remained largely unsatisfied even though the materials and implementing arts had long been available. Perhaps this was due to the fact that although those skilled in this field appreciated that a problem existed, they may not have fully appreciated that the nature of the problem was a proper understanding of the challenges of each step in use. In essence, they simply may have failed to understand the true nature of the problem and so failed to achieve the appropriate solution as evidenced in part by the pneumatic ramp invention. This is perhaps highlighted by the fact that in spite of the fact that there have been substantial attempts by those skilled in the art to fill the need, these attempts may have failed because of the limits to understanding. Instead, as the previous approaches demonstrate, there was a teaching away from the technical direction of the present invention by those skilled in the art. It might even be true that to some degree the results of the present invention might be characterized as unexpected in that it elegantly overcomes problems that have been present for years and in that it does this using elements that have been available for years.